• Airkey 2nd Generation series transmitters have been superceded by the Airkey 4th Generation series. 
•  Airkey 4th Generation transmitters are a compatible replacement with the 2nd Generation Series models AK2TX4 and AK2TX6.
• Please see Below link to see the Airkey 4th Generation product Range 

“Click Here” to See “Airkey 4th Generation Transmitters”